1. Field of the Invention
The present invention relates to a rectifier and an RFID tag thereof. More particularly, the present invention relates to a rectifier for supplying double voltage and an RFID tag thereof.
2. Description of the Related Art
With the recent advancements in the field of radio technology, a diverse range of applications of the radio frequency identification (RFID) system from a prepaid bus card and parking lot pass to a lab pass have been developed.
The RFID system consists of an RFID reader and a RFID tag, and the RFID tag can be manufactured in a card, sticker or the like, according to user convenience and usage. Basically, the RFID process is performed by exchanging an RF (radio frequency) signal between the RFID reader and RFID tag. That is, after the information for authentication which is stored in a memory formed in the RFID tag is output in the form of the RF signal, the RFID reader receives and identifies the signal.
The RFID tag replenishes necessary power using the RF signal received from the RFID reader. Meanwhile, as the power induced by the RF signal is an alternating current (AC) power, a rectifier converting the AC power into a direct current (DC) power has to be formed in the RFID tag.
The rectifier formed in the RFID tag has to meet the following.
First of all, when the RF signal received in the RFID tag is weak so that the induced AC power is weak, the rectifier has to be able to supply comparatively strong DC power to other electric elements formed in the RFID tag.
Additionally, when the RFID tag closely approach the RFID reader and a strong RF signal is received so that the induced AC power is strong, the rectifier has to take action not to damage the elements formed in the RFID tag.
Furthermore, the rectifier has to be able to supply a superior driving clock to elements in need of a driving clock.